6.1 The Constant Widgets

The const widget can contain any Lisp expression, but the user is
prohibited from editing it, which is mainly useful as a component of one
of the composite widgets.

The syntax for the const widget is:

type ::= (const [keywordargument]... [ value ])

The value, if present, is used to initialize the :value
property and can be any s-expression.

Widget: const

This will display any valid s-expression in an immutable part of the
buffer.

There are two variations of the const widget, namely
variable-item and function-item. These should contain a
symbol with a variable or function binding. The major difference from
the const widget is that they will allow the user to see the
variable or function documentation for the symbol.